GWD28-Q20,奋起的拿破仑。

20. GWD28-Q20:

In the 1820’s, anthracite coalfields opened in eastern Pennsylvania, and when canals and eventually railroads reached into the region, there were substantial supplies of coal that was exported to the nation’s growing mills, forges, factories, and railways.

1. when canals and eventually railroads reached into the region, there were substantial supplies of coal that was[h1] 

2. once canals and eventually railroads reaching into the region, there were substantial supplies of coal having been[h2] 

3. with canals and eventually railroads reaching into the region, there had been substantial supplies of coal[h3] 

4. canals and eventually railroads reached into the region, with substantial supplies of coal being[h4] 

5. as canals and eventually railroads reached into the region, substantial supplies of coal were[h5] 

答案就是e，

lz 所说的with 没有修饰，这是什么意思，请教一下，谢谢~~~~

大量的煤被运往国家正在发展的工厂，车间和铁路。（大致意思是这样）

还有，C我觉得是had been的问题吧，没有明显标志要用过去完成。

substantial supplies of（修饰语，用法就像thousands of）coal (主语)were （谓语）

不太同意ls

这样were岂不是要改成was

这个是怎么回事？怎么不妥了？？？谁能帮忙解答一下？